The present invention relates to touch sensors, examples of which are disclosed in U.S. patent application Ser. No. 14/945,083 filed Nov. 18, 2015, the entire disclosure of which is incorporated herein by reference.
The ability to sense pre-touch, or “hover” information on a touch sensor introduces many new possibilities for interacting with a touch-sensitive device. Numerous works have demonstrated the usefulness of having pre-touch information available (often described as “hover” information). See, e.g., U.S. patent application Ser. No. 14/490,363 filed Sep. 18, 2014, the entire disclosure of which is incorporated herein by reference. The detection of such hover information requires specific input hardware, often separate from the capacitive hardware that is responsible for identifying when the user is touching the sensor. Previous efforts have piggybacked on the capacitive information that is available just before the user touches, but these require a significant number of measurement frames to be analyzed before the pre-touch information can be of use, which is problematic for low-latency embodiments.